Microsoft Will Switch On Claude by Default for UK Copilot Tenants Unless Admins Opt Out
From December 9, UK Microsoft Copilot tenants that never chose a setting will get Anthropic's Claude switched on, and The Register says Microsoft's documentation puts Anthropic's processing in the United States. Admins can still block it, but the homework is due now.
Microsoft is about to make a call for British IT departments that have not made it themselves. From December 9, Anthropic's Claude models will be switched on by default for UK Microsoft Copilot tenants whose administrators have not already picked a setting, The Register reported on November 10. Leave the toggle alone and you have opted in.
The catch is where the data goes. UK tenants are not in scope for Microsoft's EU Data Boundary, and The Register says Microsoft's documentation states that Anthropic processes the relevant data in the United States. Admins now have under a month to decide whether that fits their compliance obligations, before Microsoft answers for them.
The change comes from Microsoft 365 Message Center post MC1546435, published November 10 and archived by the third party tracker ChangeCockpit. Microsoft says it will make Claude available by default in the UK "in line with other regions," and notes that Claude models "are currently disabled by default in the UK." ChangeCockpit, in its own assessment, rates the admin, user and compliance impact as high.
Silence counts as a yes
Microsoft is not forcing anyone onto Claude. The notice says admins can opt out before December 9 and can disable Claude models "at any time" after that date. Tenants that have already switched Claude off will have that choice respected, according to the notice, and tenants that already assigned Claude to specific users and groups keep those assignments.
The trap is for the organizations that never touched the setting, and for one group that did. Microsoft is retiring the option that allowed Claude only in Copilot in Microsoft 365 apps. Tenants using it will be moved to All users on December 9, the notice says, unless an admin picks No users or Specific users and groups before then. A company that deliberately chose the narrow option could wake up with the broad one.
The fix is a few clicks, per the notice. An admin with the AI Administrator or Global Administrator role goes to the Microsoft 365 admin center, opens Copilot settings, finds AI providers operating as Microsoft subprocessors, selects Anthropic and chooses who gets access. Microsoft also tells admins to warn their helpdesk and compliance teams. That is the most honest line in the notice.
Microsoft's own Learn page on Claude in Microsoft Online Services already says the company "enables Claude models on by default for most customers in commercial cloud (excluding EU/EFTA and UK)." The same page says Claude models in Copilot, Researcher, Copilot Studio, Power Platform and Copilot in Microsoft 365 apps are "currently excluded from the EU Data Boundary, and when applicable, in-country processing commitments."
"This affirms Microsoft's commitment to offering choice between leading AI models while maintaining enterprise-grade security and compliance." Microsoft, in its Learn documentation on Claude models
The Register's reply was one line long. "So long as you don't mind processing happening in the US," it wrote.
To be fair to Microsoft, Claude in Copilot is not a free for all. Anthropic works as a Microsoft subprocessor here, and the notice says Claude models in Copilot are covered by Microsoft's enterprise data protection, with the Microsoft Product Terms and Data Protection Addendum applying "except as otherwise disclosed in Microsoft Learn documentation." The notice also says Anthropic models with Data Retention sit behind a separate setting and are not part of this change. Rather than naming countries, the notice points admins to the Microsoft Online Services Subprocessors List for Claude's processing locations.
One thing this is not: an EU story. MC1546435 is addressed to tenants in the UK, and does not change anything for EU or EFTA customers.
The burden has moved to the customer, and it has a date. UK organizations that care where their Copilot prompts are processed have until December 9 to say so. After that, Microsoft says, the Claude switch is on for anyone who stayed quiet.
